java当中JDBC当中Scrollable和Updatable ResultSet的用法和Helloworld例子

马克-to-win：在前面的jdbc的Helloworld程序当中，我们接触了最简单的 Statement。那种Statement的光标只能向前移。意思就是访问完2，只能继续访问3，不能再回过头来访问1。还有就是当我们查询数据库的时 候，我们不能同时修改数据库。但在现实生活当中，我们确实有这种需求，就是如果当我们正在查询一个数据库的时候，发现某个数据有问题，想当时就修改它。对 付这种情况，sun公司专门提供了一种新的Statement。即Scrollable（可滚动的，可向前可向后）和Updatable（可更新的）的 Statement。即con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);

1.Update（更新） a row程序

以下这个程序就把第二条row的id更改成了“11”。

例：5.1.1

/*when do this experiment, if it is sql server，pls make sure you have a primary key in your table.*/

import java.sql.*;

public class TestMark_to_win {

public static void main(String[] args) throws SQLException,

ClassNotFoundException {

Class.forName("com.mysql.jdbc.Driver");

Connection con = java.sql.DriverManager.getConnection(

"jdbc:mysql://localhost:3306/test", "root", "1234");

String s = "select * from login";

/* A default ResultSet object is not updatable and has a cursor that

* moves forward only. Thus, you can iterate through it only once

* and only from the first row to the last row. It is possible to

* produce ResultSet objects that are scrollable and/or updatable.

*/

Statement stm = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_UPDATABLE);

ResultSet rs = stm.executeQuery(s);

/* boolean absolute(int row) Moves the cursor to the given row

* number in this ResultSet object.who is 1? experimentally,but

* undocumentally, the order is based on the primary key column.

*/

rs.absolute(2);

/* public void updateString(String columnName,string s)throws SQLException

* Updates the designated column with a string value. The update

* methods are used to update column values in the current row o

* the insert row. The updater methods do not update the underlying

* database; instead the updateRow or insertRow methods are called

* to update the database. */

rs.updateString("id", "11");

// rs.cancelRowUpdates();

/* public void updateRow() throws SQLException Updates the

* underlying database with the new contents of the current row of

* this ResultSet object.*/

rs.updateRow();

rs.close();

stm.close();

con.close();

}

}

更多请见：https://blog.csdn.net/qq_44594249/article/details/100765190